Net weight oil computer or the like

ABSTRACT

A net weight oil computer including a vibration densitometer and a turbine flowmeter. The flowmeter produces output pulses at a frequency directly proportional to the rate of volume flow through a pipeline. The output of the flowmeter is impressed upon the pole of a single pole, double throw electronic switch. One switch contact is connected to an indicator through a divider, a driver amplifier and a counter. The other contact is also connected to an indicator through a divider, a driver amplifier and a counter. The switch is operated by a gate generator connected from the densitometer. The gate generator produces an output pulse of a pulse width directly proportional to the reciprocal of the percent, by weight, of oil or water in the pipeline or some function thereof. A temperature probe is inserted in the line to vary the pulse width or time between pulses in accordance with oil temperature.

United States Patent November [451 Sept. 16, 1975 NET WEIGHT OILCOMPUTER OR THE LIKE [75] Inventor: Milton I-l. November, HaciendaHeights, Calif.

[73] Assignee: International Telephone and Telegraph Corporation, NewYork, NY.

[22] Filed: Oct. 11, 1974 21 Appl. No.: 514,222

[52] US. Cl 235/15L35; 73/32 A; 73/61.l R

[51] Int. Cl. G06G 7/75; GOIF 1/00 [58] Field of Search 73/32 A, 61.1 R,194 B; 235/l51.35

[56] W References Cited UNITED STATES PATENTS 3,385.108 5/1968 Rosso73/194 R 3,774,448 11/1973 Gass et a1 73/61.l R

Primary ExaminerEugene G. Botz Attorney, Agent, or F irm-A. DonaldStolzy [5 7 ABSTRACT A net weight oil computer including a vibrationdensitometer and a turbine flowmeter. The flowmeter produces outputpulses at a frequency directly proportional to the rate of volume flowthrough a pipeline. The output of the flowmeter is impressed upon thepole of a single pole, double throw electronic switch. One switchcontact is connected to an indicator through a divider, a driveramplifier and a counter. The other contact is also connected to anindicator through a divider, a driver amplifier and a counter. Theswitch is operated by a gate generator connected from the densitometer.The gate generator produces an output pulse of a pulse width directlyproportional to the reciprocal of the percent, by weight, of oil orwater in the pipeline or some function thereof. A temperature probe isinserted in the line to vary the pulse width or time between pulses inaccordance with oil temperature.

18 Claims, 6 Drawing Figures PREAMPL lF/ER,

NET WEIGHT OIL COMPUTER OR THE LIKE BACKGROUND OF THE INVENTION Thisinvention relates to devices for determining the character of fluids,and more particularly, to apparatus for producing signals in accordancewith the mass of a fluid.

In the past, it has been unknown to measure the percent, by weight, ofoil in a mixture of oil and water flowing in a pipeline.

SUMMARY OF THE INVENTION In accordance with the systems of the presentinvention, the abovedescribed and other difficulties are overcome byproviding a net weight oil computer.

An outstanding feature of the invention is that oil and water mass orweight can be indicated. This is important because the heating capacityofa volume of oil varies with temperature but is independent of theweight or mass thereof. Thus, for billing, blending or mixing purposes anet weight oil computer is extremely important.

The above-described and other advantages of the present invention willbe better understood from the following detailed description whenconsidered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which are to beregarded as merely illustrative:

FIG. 1 is a diagrammatic view of the net oil compputer of the presentinvention;

FIG. 2 is a diagrammatic view of a gate generator shown in FIG. 1; g N

FIG. 3 is a schematic diagram of one of high and low limit detectorsshown in FIG. 2;

FIG. 4 is a schematic diagram of the other of the high and low limitdetectors shown in FIG. 2;

FIG. 5 is a first alternative embodiment of the net weight oil computerof the presentinvention; and

FIG. 6 is a second alternative embodiment of the net weight oil computerof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS THE NET WEIGHT OIL COMPUTER OFFIG. 1

A net wieght oil computer constructed in accordance with the presentinvention is shown in FIG. 1. This computer has components mounted in apipeline 473. One component is a densitometer probe 472 having itsoutput connected to a transmitter circuit 401. The probe 472 and thetransmitter circuit 401 form a densitometer which may be identical to ordifferent from that disclosed in copending application Ser. No. 187,948now US. Pat. No. 3,525,917 filed Oct. 12, 1971, by Gerald L. Schlatterand Charles E. Miller for Fluid Sensing Systems. By this referencehereto, the entire contents of said copending application Ser. No.187,948 is hereby incorporated herein herat. The said copendingapplication Ser. No. 187,948 isassigned to the assignee of the instantapplication.

Circuit 401 produces an output current which is directly proportional tothe density of the mixture of water and oil in pipeline 473.

In FIG. 1, the net weight oil computer also includes a turbine flowmeter402 which has a turbine bladed rotor 403 and a stator 404. Flowmeter 402also has a magnetic pickup 405. Flowmeter 402 is entirely conventionaland produces a pulse train on an output lead 406. The pulse repetitionfrequency (PRF) of the pulses on lead 406 is directly proportional tothe volume flow rate within pipe1ine473. In other words, the flow rateis the rate of volume flow of both oil and water combined, that is themixture thereof. The output of flowmeter 402 is impressed on the pole407 of a conventional electronic switch 408 in an output circuit 471.Switch 408 May, however, be a relay, an electronic switch or otherwise.Switch 408 has contacts 409 and 410. Contact 409 is connected to aconventional indicater 411 via a conventional divider 412, aconventional driver amplifier 413 and a conventional counter 414.Contact 410 is connected to a conventional indicator 415 through aconventional divider 416, a conventional driver amplifier 417 and aconventional counter 418.

Flowmeter 402 is connected to switch pole 407 through a conventionalpreamplifier 419 and a conventional monostable multivibrator 420.

Switch 408 is operated by a gate generator 400 that receives inputsignals from transmitter circuit 401 and a temperature probe 421.Densitometer probe 47 2, turbine rotor 403 and temperature probe 421 areall immersed in the mixture of oil and water flowing in pipeline 473.

Dividers 412 and 416 may be employed to cause indicators 411 and 415 toread directly in pounds of oil and pounds of water, respectively.

If the output pulses of gate generator 400 are positive, as describedhereinafter, pole 407 will engage one of the contacts 409 and 410. Thatis, the engagement occurs during the width of the pulse. Conversely,during the time between pulses, pole 407 will engage the other of thecontacts 409 and 410.

Gate generator 400 is shown in FIG. 2 including a conventional regulatedsource of potential 422 which places a voltage -E on a contact 423 of aconventional electronic switch 424. Source 422 also places a voltage Eon a contact 425. Switch 424 is a single-pole, double-throw switchhaving a pole 426. Switch 424 may be a relay, an electronic switch orotherwise. A conventional integrator 427 is connected from the pole ofswitch 424 to a high limit detector 428, a low limit detector 429 and aconventional comparator 430. The output of comparator 430 is impressedupon switch 408 shown in FIG. 1 over a lead 474.

If desired, all of the structures shown in FIG. 1 may or may not beidentical to the corresponding structures disclosed in said copendingapplication Ser. No. 187,948 except gate generator 400. Detectors 428and 429 are connected, respectively, to the set and reset inputs of aconventional flip-flop 434. The 0 output of flip-flop 434 operatesswitch 424.

High limit detector 428 causes the output of integrator 427 to declineafter a predetermined high level is reached. Conversely, low limitdetector 429 causes the output of integrator 427 to increase once apredetermined low level is reached. Thus, the output of the integrator427 is a triangular wave indicated at 475, the peaks of which are thepredetermined high limit and the valleys of which are the predeterminedlow limit. Thus, when the 0 output of flip-flop 434 is high, switch pole426 is in engagement with contact 423. Conversely, when the 0 output offlip-flop 434 is low, pole 426 is in engagement with contact 425.

The output of circuit 401 in FIG. 1 is a current analog of density.Circuit 401 may or may not be identical to thecorresp'onding circuit insaid copending application Ser. No. 187,948. Converter 435 converts thecurrent analog to a voltage analog. The output of converter 435 is.impressed upon comparator 430 through a conventional analog divider 470.Limit detectors are shown in both of FIGS. 3 and 4. The detector of FIG.3 may be one of the high and low limit detectors 428 and 429,respectively, shown in FIG. 2. FIG. 4 is then the other of the high andlow limit detectors 428and 429, respectively.

In FIGS. 3 and 4, variable resistors 476 and 477, respectively, areadjusted in accordance with the densities of the water and oil,respectively, in pipeline 473. The water and oil densities are obtainedby taking a sample of the mixture thereof in pipeline 473, and thenputting the sample through a centrifuge. The densities of the oil andwater so separated is then measured. The variable resistors 476 and 477are then set in proportion to the respective water and oil densitiesmeasured. Various densities may be encountered due to impurities,dissolved solids and otherwise. The specific gravity of the water inpipeline 473 might typically be 1.07. The oil in pipeline 473, which mayor may not be crude oil, may have a typical specific gravity of .85.

Comparator 430, shown in FIG. 2, produces an output pulse at 4780f atime width equal to the time that the triangular wave output ofintegrator 427 exceeds the magnitude of the voltage at the output ofanalog divider 470. Although it is unobvious and quite unexpected, thewidth of the output pulses of comparator 430 is either directlyproportional to the percent, by weight, of Water flowing in pipeline 473or is directly proportional to the percent, by weight, of oil flowing inpipeline 473 depending upon whether the water density d is larger thanthe oil density d or vice versa, and depending upon which-embodiment ofthe present invention is employed or which modification thereof isemployed. The same is true of the time between pulses.

Temperature probe 421 supplies a correction because the density of oilvaries enough with temperature that a noticeable improvement in accuracycan be obtained by using this temperature correction. A temperaturecorrection for changes in the water density is frequently unnecessary.

In FIG. 3,junctions are provided at 10, 11 and 12. A resistor 13 isconnected from junction 10 to a potential E A resistor 14 is connectedfrom junction to a potential E which may be ground. Resistors .13 and 14form a voltage divider establishing a potential at junction 10 which isadded to a feedback potential established by resistor 476 connectedbetween junctions 11 and 12. It will be noted that a portion of thecircuit of FIG. 3 is a conventional analog divider. A resistor 15 isconnected between junctions 10 and 11.

A differential amplifier 16 is also shown in FIG. 3 having an invertinginput lead 17 connected from junction 11, and a non-inverting input lead18 connected to ground. Differential amplifier 16 has an output lead 19connected to junction 12.

A second differential amplifier is provided at 20 in FIG. 3 having firstand second input leads 21 and 22, respectively. Input lead 21 isconnected from junction 12. Input lead 22 is connected from the outputof integrator 427 illustrated in FIG. 2.

Differential amplifier 20 has an output lead 23 which is connected toone of the input leads of flip flop 434.

The arrangement of FIG. 4 is not considerably different from thearrangement of FIG. 2. In FIG. 4, junctions are provided'at 24, 25 and26. A resistor 27 is connected from junction 24 to potential E...Another resistor 28 is connected from junction 24 to potential E,, orground. As before, resistors 27 and 28 form a voltage dividerestablishing a potential at junction 24.

In FIG. 4, again, a first differential amplifier 29 forms a part of ananalog divider. Differential amplifier 29 has an inverting input lead 30connected from junction 25, and a non-inverting input lead 31 connectedto ground. An adding resistor 32 is connected between junctions 24 and25. I

In FIG. 4, variable resistor 477 and the thermistoror temperature probe421 are connected in succession in that order in series from junction 25to junction 26.

Differential amplifier 29 has an output lead 33 connected to junction26. A

In FIG. 4, a second differrential amplifier is provided at 34 havingfirstand second input leads 35 and 36. Input lead 35 is connected fromjunction 26. Input lead 36 is connected from the output of integrator427 shown in FIG. 2. Differential amplifier 34 has an output lead 37which is connected to one of the input leads to flip flop 434 shown inFIG. 2.

It will be noted that, thus far, it has not been stated which of the twoleads 21 and 22 shown in FIG. 3 are the inverting and non-invertinginput leads of differential amplifier 20. The same is true of the inputleads 3 5 and 36 of the differentia amplifier 34 shown in F IGI 4. Thereason for this is that the water density is set in accordance withvariable resistor 476 in FIG. 3, and the oil density is set inaccordance with resistor 477 shown in FIG. 4, and the water density mayor may not exceed the oil density. This means that the high limitdetector 428 shown in FIG. 2 may be either the detector shown in FIG. 3or the detector shown in FIG. 4. This also means that the low limitdetector 429 shown in FIG. 2 may be either the detecor shown in FIG. 3or the detector shown in FIG. 4. Nevertheless, if the high limitdetector 428 is the detector of FIG. 4, the low limit detector 429 mustbe the detector of FIG. 3, and vice versa.

Should the water density exceed the oil density, the detector of FIG. 3is the low limit detector 429, and the output lead 23 of differentialamplifier 20 is connected to the reset input of flip flop 434. When thisis the case, the output lead 37 of differential amplifier 34 shown inFIG. 4 is thus then connected to the set input of the flip flop 434shown in FIG. 2. At the same time, the lead 21 of differential amplifier20 shown in FIG. 3 is the inverting input lead of differential amplifier20, and the lead 22 is the non-inverting input lead thereof. While allthe foregoing connections are made, the lead 35 of differentialamplifier 34 shown in FIG. 4 is the noninverting'input lead thereof, andlead 36 is the inverting input lead thereof.

When=the oil density exceeds the'water density, the detector of FIG. 3becomes the high limit detector 428 and output lead 23 of FIG. 3 is thenconnected to the set input of flip flop 434. Similarly, the output lead37 in FIG. 4 is connected to the reset input of flip flop 434, and thedetector of FIG. 4 is the low limit detector 429. Under all theseconditions then, other connections are similarly reversed, i.e. lead 21of differential amplifier 20 becomes the non-inverting input leadthereof, input lead 22 thereof becomes the inverting input lead thereof,lead 35 in FIG. 4 becomes the inverting input lead of differentialamplifier 34, and lead 36 of differ ential amplifier 34 in FIG. 4becomes the non-inverting input lead of differential amplifier 34.

When the water density is larger than the oil density, T is the width ofthe pulses 478 as shown in FIG. 2, and T, is the time between pulse 478as shown in FIG. 2. However, if nothing is changed but resistors 476 and477 in FIGS. 3 and 4, respectively, T becomes the time between pulses478, and T, becomes the width of the pulses 478. This reversal occurswhen a reversal occurs between the high and low limit detectors 428 and429 wherein the detectors of FIGS. 3 and 4 are reversed therein asaforesaid.

The term T when the water density is larger than the oil density, isequal to the width of the pulses 478 and is directly proportional to thepercent water flowing in pipeline 473 shown in FIG; 1. At the same time,the term T, is directly proportional to the percent oil flowing in thepipeline 473 shown in FIG. 1.

The embodiment of FIGS. 1 to 4, inclusive, is not perfectly accurate,but in many cases is extremely accurate and may be accurate for allpractical purposes. The embodiment of FIGS. 1 to 4, inclusive, isextremely accurate when the percent change in the oil density withtemperature is extremely small over the time period which is equal tothe sum of T and T,.

The output of integrator 427 is illustrated by the triangular waveform475 shown in FIG. 2. The dimensions l/d,,. and l/d are the reciprocalsof water and oil densities and are directly proportional to, or viceversa, the voltage amplitude dimensions of the high and low limits whenthe water density is larger than the oil density. In this case, thesubscripts w and would be reversed if the oil density exceeded the waterdensity.

In FIG. 2, the slope of triangular waveform 475 is either positiveornegative, but its absolute value in either case is a constant. Theintegrator 427 is thus only free running in that it rises to the highlimit and falls to the low limit. For all practical purposes, it isunnecessary to compensate for temperature expansion and contraction ofthe Water. The term (1,, is therefore always constant after resistor 476has been properly set to the measured value of the water density. Ifdesired, resistors 476 and 477 may be potentiometers operated by a knobhaving indicia thereon for correlation with a fixed indexed mark.

The temperature of the mixture flowing in pipeline 473 shown in FIG. Imay vary little the resistance of the probe 421 shown in FIGS. 1 and 4.Should the temperature of the mixture of the oil and water flowing inpipeline 473 shown in FIG. 1 vary greatly, the embodiment of the presentinvention shown in FIGS. 1 to 4, inclusive, still may be employed solong as the temperature does not vary at a rapid rate. I

In the embodiments of the present invention illustrated in FIGS. 5 and6, the outputs thereof are accurate independent of the rate of change ofthe temperature of the oil and water mixture flowing in the pipeline 473shown in FIG. 1 with respect to time.

In FIG. 2, the output of analog divider 470 is directly proportional tothe reciprocal of d,,,, mean density. When the triangular waveform 475exceeds the output of analog divider 470,,pulses 478 are produced. Theterm T, is thus determined when waveform 475 falls below the output ofanalog divider 470.

In FIG. 3, all of the structure except differential amplifier 20actually supplies at junction 12 and over lead 21 a DC. voltage directlyproportional to the reciprocal of water density.

'In FIG. 4, all the structure therein except the differential amplifier34 actually supplies at junction 26 and over lead 35 a DC. voltagedirectly proportional to the reciprocal of the oil density.

In accordance with the present invention, one embodiment thereof isdisclosed herein in FIGS. 1 to 4 inelusive, a second in FIG. 5, and athird in FIG. 6. Each of these three embodiments compute the percent, byweight, of oil and/or water in a different way, and by unexpected andunobvious equations. These equations follow.

If d,,. d switch 408 inFIG. 1 is constructed to have its pole 407 inengagement with contact 409 between pulses 478 in FIG. 2, and pole 407engages contact 410 during the widths of pulses 478, the detector ofFIG. 3 is connected as the low limit detector 429 and the detector ofFIG. 4 is connected as the high limit detector 428.

In accordance with the foregoing, the high limit is directlyproportional to the reciprocal of d and the low limit is directlyproportional to the reciprocal of d,,.. The output of analog divider 470is directly proportional to the reciprocal of the average density d,, ofthe mixture of oil and water in pipeline 473.

In the foregoing case, the width T,,. of a pulse 478 is directlyproportional to percent by weight of water and the time between pulsesT, is directly proportional to percent by weight of oil. By using aninverter at the output of comparator 430 the converse would be true.Thus, one of the times T and T, is always equal to In the embodiments ofFIGS. Sand 6 the comparator input to the output circuit is similar tothe train of pulses 478 in FIG. 2 except that one of the times T and T,is

where K is a positive constant, and the other of the times T,, and T, is

while the other of the times T and T OPERATION OF THE NET WEIGHT OILCOMPUTER OF FIG. 1

In the operation of the embodiment of the invention illustrated in FIG.1, densitometer probe 472 in combination with transmitter circuit 401delivers a current to gate generator 400 which is directly proportionalto the mixture of oil and water flowing in pipeline 473. Gate generator400 then produces output pulses of widths which are directlyproportional to the percent, by weight, of oil flowing in pipeline 473.Temperature probe 421 supplies an input to'gate generator 400 to adjustthe output in accordance with changes in the temperature of the oilflowing in pipeline 473, this tern perature being the same as thetemperature of the mixture of oil and water flowing in pipeline 473.Switch 408 in output circuit 471 is constructed todeliver' pulses tocounters 414 and 418 through driver amplifiers 413 and 417,respectively, and dividers 412 and 416, respectively, so that indicators411 and 415, respectively, will indicate the total mass of oil andwater, respectively, which has passed through that portion of pipeline43 shown in FIG. 1.

Gate generator 400 controls the position of the pole 407 of switch 408via lead 474 to divert, alternately, pulses received from the output ofmonostable multivibrator 420 connected to-pole 407 to dividers 412 and416.

Note will be taken that all of the four outputs of transmitter 401 inFIG. 1, current-to-voltage converter 435 in FIG. 2, and the meansdensity analog sources illustrated in both FIGS. 5 and 6 are directlyproportional to the mean, i.e. average density of the mixture of oil andwater in pipeline 473 shown in FIG. 1. These same said four outputs arealso directly proportional to the mean specific gravity of the mixture,the difference between density and specific gravity only being due tothe constant factor of the density of pure water at a constant referencetemperature. Thus, for use herein and in the claims, any form of thephrase specific gravity is hereby defined to include densityand viceversa.

Note will be taken that the water in pipeline 473 will not normally bepure and may contain sodium chloride and/or other contaminants in or outof solution.

THE NET WEIGHT OIL COMPUTER OF FIG. 5

In FIG. 5, oil density, water density and mean density analog sourcesare illustrated at 38, 39 and 40. Two analog subtractors 41 and 42 areillustrated with two analog multipliers 43 and 44. An analog divider isprovided at 45. Two comparators are provided at 46 and 47. Adifferentiator is provided at 68. An integrator is provided at-69. Aturbine meter is provided at put circuit is provided at 71.

Analog subtractor41receives inputs fromsources 38 and 39. Multiplier 43receives inputs from the output of analog subtractor 41 and the outputof source 40.

Analog subtractor 42 receives inputs from sources 39 and 40, andimpresses an output upon analog multiplier 44. Analog multiplier 44receives. another input from the output of analog subtractor 42.

The outputs of multipliers 43 and 44 are impressed upon analog divider.45.. I

The output of analog divider 45 is impressed upon a comparator 46. Theoutput of comparator 46 is impressed upon output circuit 71. Bothcomparators 46 and 47 receive inputs from the output of integrator 69.The output of comparator47 is impressed upon the reset input ofintegrator 69 via differentiator 68.

The output of turbine meter 70 is impressed upon output circuit 71. V

70. An out- Source 33 th be identical to FIG. 4 without the input fromintegrator 427 andwithout differential amplifier 34 and its leads 35, 36and 37. The output of source 38 would then be taken from junction 26shown in FIG. 4.

Similarly, source 39 may be identical to FIG. 3 except for theinputfromintegrator 427 whichwould be omitted with differentialamplifier 20 and its leads 21, 22 and 23. The outputof source 39 wouldthen be taken from the junction 12 shown in FIG. 3.

'Source 40 may be probe 472 and transmitter circuit 401 shown in FIG. 1with converter 435, but without analog divider 470. f

Subtractors 41 and 42 may be entirely conventional. The same is true ofmultipliers 43am '44, and divider 45; The same is also true ofcomparators 46 and 47, differentiator 68 and integrator Turbine meter 70may be all the structure indicated at 402, 419 and 420 in FIG. 1.

Output circuit 71 may be identical to output circuit 471 shown in FIG.1, if desired.

The embodiment of the present invention illustrated in FIG. 5 computesoil'and water in percent by weight and applies it'to outputcircuit 71from the output lead of comparator 46 in accordance with one of theexpressions (3) and (5) The output of analog divider 45 is directlyproportional to one of the expressions (3) or (5 Comparator 46 andintegrator 69 simply'convert the analog output of analog divider 45 to apulse width or to a time between pulses. Comparator 46 may, for example,produce an output and impress the same upon output circuit 71'when theoutput of integrator 69 rises to the level of the amplitude of theoutput of analog divider 45 or falls to the amplitude of such output.

Comparator 47 resets integrator 69 after a time which is directlyproportional to K This is true because the sum of the expressions (3)and (4) is equal to K Similarly, the sum of the'expressions (5) and (6)is equal to K In the embodiment of the present invention illustrated inFIG; 6,.the component parts there shown at 38, 39, 40, 41, 43, 42', 44',45', 47, 46', 69', 71', 68 and 70' may be. identical to respectivecorresponding parts 38, 39, 40, 41, 43, 42, 44, 45, 47, 46, 69, 71, 68and 70 shown in FIG. 5. FIG. 6 is identical to FIG. 5 except for theconnections fromsources 38, 39' and 40 to-subtractors 41' and 42', and.to multipliers 43 and 44. The Operation of both FIGS. 5 and 6 is thuscommon except for the inputs ,used. As connected, FIG. 6 computespercent, by weight, of both oil and water in accordance with either oneof the expressions (4) or (6). The output of analog divider 45 "is thusdirectly proportional to the expression (4) or the expression (6).

The phrase utilization means is hereby defined for use herein and foruse in the claims to mean any means for utilizing the outputs of allthree of the embodiments of the present invention disclosed herein. Forexample, the output from switch contact 409 in FIG. 1 is usefulindependent of the output from switch contact 410. Moreover, the outputfrom switch contact 409 and/or the output from switch contact 410 may beimpressed on indicators 411 and 415 as shown, on a process controller orotherwise. v l

The word fluid asused herein and as used in the claims is hereby definedto mean either a gas or a liquid unless the invention is operable onlywith a liquid.

The computations made herein are by no means limited to computationsmade by analog computers. The invention as disclosed and claimed hereinmay also be practiced through the use of digital computers.

The phrase change the connection of a switch is hereby defined for useherein and for use in the claims to mean to open or close the'switch;

As is conventional, the dimension T shown in FIG. 2 precisely as shownand not otherwise changed would be defined as the width of one or moreof the pulses 478. 1

In FIG. 2, the term T, precisely as shown is the time between thetrailing edge of the left-hand pulse 478 and the leading edge of theright-hand,pulse478.n

What is claimed is: 1 t it l. A net weight fluid computer for-producinganoutput directly proportional to the total mass. flow of at least oneof first and second fluids flowing-as a mixture in a pipeline, saidcomputer comprising: first means connected with the pipeline forproducing first pulses at a pulse repetition frequency directlyproportional to the volume .rate of total flow in the pipeline; secondmeans connected with the pipeline for producing an output directlyproportional to the average density d of the mixture in the pipeline;third means for producing an output directly proportional to the densityd of the first fluid; fourth means for producing an output directlyproportional to the density d of the second fluid; a switch havingfirstinput lead connected from said first means to receive said firstpulses,-said switch having at least one output lead connected therefrom,said switch having a second input lead and being electrically operableupon reciept of a pulse on said second input lead to change theconnection between the first input and the output lead of said-switch;and fifth means connected from said second, third and fourth means toreceive the outputs thereof and adapted to impress second pulses on thesecond input lead of said switch to cause first pulses to be passed andinterrupted alternately from the first input lead to the output lead ofsaid switch, said fifth means causing said second pulses to have a timewidth T said fifth means causing said second pulses to be generated at arate such that the time between the trailing edge of one second pulseand the leading edge of the next succeeding second pulse is T,, saidfifth means causing one of said times T and T, to be equal to thefollowing expression where K is a constant that is positive when and isnegative when said fifth means causing the other of said times T and Tto be equal to said switch having pulses appearing on said output leadthereof directly proportional, in number, to the'total mass flow of saidone fluid. t I

2. The invention as defined in claim 1, wherein utilization means areconnected from the output lead of said switch. Y

3. The invention as defined in claim 2, wherein said utilization meansincludes a pulse counter connected from the output lead of said switch,and an indicator to indicate the number counted by said counter, all ofsaid means being constructed to cause said counter to read in total massflow units. a

4. The invention as defined in claim 3 wherein said second meansincludes a densitometer" having'a probe immersed in the mixture.

5. The invention as defined in claim 4', whereinsaid third meansincludes a temperature sensitive probeimmersed in the mixture to varythe output of said'third means in direct'proportion to the temperatureof the mixture. I

6. The invention as defined in claim 5, wherein said' first meansincludes a device mounted in the pipeline.

7. A net weight fluid computer for producing an out-' put directlyproportional to the total mass flow of at least one of first and secondfluids flowing as a mixture in a pipeline, said computercomprisingz'first means connected with the pipeline for producing firstpulses at a pulse repetition frequency directly proportional tothe'volume rate of total flow in the pipeline; second means connectedwith the pipeline for producing an output directly proportional to theaverage density d of the mixture in the pipeline; third means forproducing an output directly proportional to the density d of the firstfluid; fourth means for producing an output directly proportional to thedensity d of the second fluid; a switch having first input leadconnected from said first means to receive said first pulses, saidswitch having at least one output lead connected therefrom, said switchhaving a second input lead and being electrically operable upon receiptof a pulse on said second input lead to change the connection betweenthe first input and the output lead of said switch; and fifth meansconnected from said second, third and fourth means to receive theoutputs thereof and adapted to impress second pulses on the second inputlead of said switch to cause first pulses to be passed and interruptedalternatley from the first input lead to the output lead of said switch,said fifth means causing said second pulses to have a time width T saidfifth means causing said secwhere K is a positive constant,

said fifth means causing the other of said times T and T, to be equal tothe following expression said switch having pulses appearing on saidoutput lead thereof directly proportional, in number, to the total massflow of said one fluid.

8. The invention as defined in claim 7, wherein utilization means areconnected from the output lead of said switch.

9. The invention as defined in claim 8, wherein said utilization meansincludes a pulse counter connected from the output lead of said switch,and an indicator to indicate the number counted by said counter, all ofsaid means being constructed to cause said counter to read in total massflow units. 1

10. The invention as defined in claim 9, wherein said second meansincludes a densitometer having a probe immersed in the mixture.

11. The invention asdefined in claim 10, wherein said. third meansincludes a temperature sensitive probe immersed in the mixture to varythe output of said third means in direct proportion to the temperatureof the mixture. I

12. The invention as defined in claim 11, wherein said first meansincludes a device mounted in the pipeline.

13. A net weight fluid computer for producing an output directlyproportional to the total mass flow of at least one of first and secondfluids flowing as a mixture in a pipeline, said computer comprising:first means connected with the pipeline for producing first pulses at apulse repetition frequency directly proportional to the volume rate oftotal flow in the pipeline; second means connected with the pipeline forproducing an output directly proportional to the average density d ofthe mixture in the pipeline; third means for producing an outputdirectly proportional to the density d of the first fluid; fourth meansfor producing an output directly proportional to the density d,,. of thesecond fluid; a switch having first input lead connected from said firstmeans to receive said first pulses, said switch having at least oneoutput lead connected therefrom, said switch having a second input leadand being electrically operable upon receipt of a pulse on said secondinput lead to change the connection between the first input and theoutput lead of said switch; and fifth means connected from said second,third and fourth means to receive the outputs thereof and adapted toimpress second pulses on the second input lead of said switch to causefirst pulses to be passed and interrupted alternately from the firstinput lead to the output lead of said switch, said fifth means causingsaid second pulses to have a time width T said fifth means causing saidsecond pulses to be generated at a rate such that the time between thetrailing edge of one second pulse and the leading edge of the nextsucceeding second pulse is T,, said fifth means causing one of saidtimes T and T, to be equal to the following expression d, d, d,

where K is a positive constant,

said switch having pulses appearing on said output lead thereof directlyproportional, in number, to the total mass flow of said one fluid.

14. The invention as defined in claim 13, wherein utilization means areconnected from the output lead of said switch.

15. The invention as defined in claim 14, wherein said utilization meansincludes a pulse counter connected from the output lead of said switch,and an indicator to indicate the number counted; by said counter, all ofsaid means being constructed to cause said counter to read in total massflow units.

16. The invention as defined in claim 15, wherein said second meansincludes a densitometer having a probe immersed in the mixture.

17. The invention as defined in claim 16, wherein said third meansincludes a temperature sensitive probe immersed in the mixture to varythe output of said third means in direct proportion to the temperatureof the mixture.

18. The invention as defined in claim 17, wherein said first meansincldes a device mounted in the pipeline.

1. A net weight fluid computer for producing an output directlyproportional to the total mass flow of at least one of first and secondfluids flowing as a mixture in a pipeline, said computer comprising:first means connected with the pipeline for producing first pulses at apulse repetition frequency directly proportional to the volume rate oftotal flow in the pipeline; second means connected with the pipeline forproducing an output directly proportional to the average density dm ofthe mixture in the pipeline; third means for producing an outputdirectly proportional to the density do of the first fluid; fourth meansfor producing an output directly proportional to the density dw of thesecond fluid; a switch having first input lead connected from said firstmeans to receive said first pulses, said switch having at least oneoutput lead connected therefrom, said switch having a second input leadand being electrically operable upon reciept of a pulse on said secondinput lead to change the connection between the first input and theoutput lead of said switch; and fifth means connected from said second,third and fourth means to receive the outputs thereof and adapted toimpress second pulses on the second input lead of said switch to causefirst pulses to be passed and interrupted alternately from the firstinput lead to the output lead of said switch, said fifth means causingsaid second pulses to have a time width Tw, said fifth means causingsaid second pulses to be generated at a rate such that the time betweenthe trailing edge of one second pulse and the leading edge of the nextsucceeding second pulse is Tt, said fiFth means causing one of saidtimes Tw and Tt to be equal to the following expression
 2. The inventionas defined in claim 1, wherein utilization means are connected from theoutput lead of said switch.
 3. The invention as defined in claim 2,wherein said utilization means includes a pulse counter connected fromthe output lead of said switch, and an indicator to indicate the numbercounted by said counter, all of said means being constructed to causesaid counter to read in total mass flow units.
 4. The invention asdefined in claim 3, wherein said second means includes a densitometerhaving a probe immersed in the mixture.
 5. The invention as defined inclaim 4, wherein said third means includes a temperature sensitive probeimmersed in the mixture to vary the output of said third means in directproportion to the temperature of the mixture.
 6. The invention asdefined in claim 5, wherein said first means includes a device mountedin the pipeline.
 7. A net weight fluid computer for producing an outputdirectly proportional to the total mass flow of at least one of firstand second fluids flowing as a mixture in a pipeline, said computercomprising: first means connected with the pipeline for producing firstpulses at a pulse repetition frequency directly proportional to thevolume rate of total flow in the pipeline; second means connected withthe pipeline for producing an output directly proportional to theaverage density dm of the mixture in the pipeline; third means forproducing an output directly proportional to the density do of the firstfluid; fourth means for producing an output directly proportional to thedensity dw of the second fluid; a switch having first input leadconnected from said first means to receive said first pulses, saidswitch having at least one output lead connected therefrom, said switchhaving a second input lead and being electrically operable upon receiptof a pulse on said second input lead to change the connection betweenthe first input and the output lead of said switch; and fifth meansconnected from said second, third and fourth means to receive theoutputs thereof and adapted to impress second pulses on the second inputlead of said switch to cause first pulses to be passed and interruptedalternatley from the first input lead to the output lead of said switch,said fifth means causing said second pulses to have a time width Tw,said fifth means causing said second pulses to be generated at a ratesuch that the time between the trailing edge of one second pulse and theleading edge of the next succeeding second pulse is Tt, said fifth meanscausing one of said times Tw and Tt to be equal to the followingexpression
 8. The invention as defined in claim 7, wherein utilizationmeans are connected from the output lead of said switch.
 9. Theinvention as defined in claim 8, wherein said utilization means includesa pulse counter connected from the output lead of said switch, and anindicator to indicate the number counted by said counter, all of saidmeans being constructed to cause said counter to read in total mass flowunits.
 10. The invention as defined in claim 9, wherein said secondmeans includes a densitometer having a probe immersed in the mixture.11. The invention as defined in claim 10, wherein said third meansincludes a temperature sensitive probe immersed in the mixture to varythe output of said third means in direct proportion to the temperatureof the mixture.
 12. The invention as defined in claim 11, wherein saidfirst means includes a device mounted in the pipeline.
 13. A net weightfluid computer for producing an output directly proportional to thetotal mass flow of at least one of first and second fluids flowing as amixture in a pipeline, said computer comprising: first means connectedwith the pipeline for producing first pulses at a pulse repetitionfrequency directly proportional to the volume rate of total flow in thepipeline; second means connected with the pipeline for producing anoutput directly proportional to the average density dm of the mixture inthe pipeline; third means for producing an output directly proportionalto the density do of the first fluid; fourth means for producing anoutput directly proportional to the density dw of the second fluid; aswitch having first input lead connected from said first means toreceive said first pulses, said switch having at least one output leadconnected therefrom, said switch having a second input lead and beingelectrically operable upon receipt of a pulse on said second input leadto change the connection between the first input and the output lead ofsaid switch; and fifth means connected from said second, third andfourth means to receive the outputs thereof and adapted to impresssecond pulses on the second input lead of said switch to cause firstpulses to be passed and interrupted alternately from the first inputlead to the output lead of said switch, said fifth means causing saidsecond pulses to have a time width Tw, said fifth means causing saidsecond pulses to be generated at a rate such that the time between thetrailing edge of one second pulse and the leading edge of the nextsucceeding second pulse is Tt, said fifth means causing one of saidtimes Tw and Tt to be equal to the following expression
 14. Theinvention as defined in claim 13, wherein utilization means areconnected from the output lead of said switch.
 15. The invention asdefined in claim 14, wherein said utilization means includes a pulsecounter connected from the output lead of said switch, and an indicatorto indicate the number counted by said counter, all of said means beingconstructed to cause said counter to read in total mass flow units. 16.The invention as defined in claim 15, wherein said second means includesa densitometer having a probe immersed in tHe mixture.
 17. The inventionas defined in claim 16, wherein said third means includes a temperaturesensitive probe immersed in the mixture to vary the output of said thirdmeans in direct proportion to the temperature of the mixture.
 18. Theinvention as defined in claim 17, wherein said first means incldes adevice mounted in the pipeline.